Up until recently petroleum products were sufficiently inexpensive that although engine oil is sometimes recycled when collected at a service station, no serious thought was given to recycling used crankcase oil when changed by the home mechanic. The current high prices of petroleum products however was made the prospect of saving crankcase oil either to be re-refined and used again as crankcase oil or simply used as heating oil, more practical. In fact many stoves which have been developed in the last few years to accommodate a variety of different fuels advertise that they can use used crankcase oil without clogging.
Aside from the conversation aspects of recycling oil and the possibility of saving money, it is common knowledge that the oil changing operation is an unpleasant and messy job which ends up in several quarts of oil lying in an oil change pan with no place to put it. Typical solutions involve trying to pour the oil into plastic gallon milk containers or just dumping it in a hole one has in the backyard. Dumping becomes increasingly impractical with increased housing density and condominium living, and in any event more often than not, no matter how the job is done, some of the oil will have slopped into the pavement or onto elaborately arrayed newspapers put under the car to protect the pavement.